Abstract After a standard heat treatment and subsequent isothermal aging at 750 °C for 8,220 h, the tensile deformation behavior of a novel precipitation-hardened Ni–Fe-base superalloy HT700T containing around 23 vol% of γ′ precipitates is studied at 750 °C. It is found that the work-hardening rate decreases monotonously with plastic strain. Transmission electron microscopy observations on the specimens stretched to various magnitudes of plastic strain reveal that Orowan looping prevails at the very beginning of plastic deformation. Whereas, as plastic deformation proceeds, more and more isolated superlattice stacking faults are produced within the γ′ precipitates although numerous dislocation loops have surrounded the same γ′ precipitates, suggesting shearing of γ′ precipitates by {111} slip systems plays a more and more important role in the plastic deformation with strain. Based on the experimental observations, the relationship between the operative deformation mechanisms and the work-hardening rate of HT700T is discussed.

中文翻译：

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新型镍铁基高温合金 HT700T 750 °C 拉伸变形机制研究

摘要 在标准热处理和随后在 750 °C 下等温时效 8,220 h 后，研究了一种含有约 23 vol% γ'沉淀物的新型沉淀硬化 Ni-Fe 基高温合金 HT700T 在 750 °C 下的拉伸变形行为。 . 发现加工硬化率随塑性应变单调下降。对拉伸到各种塑性应变幅度的试样进行透射电子显微镜观察表明，在塑性变形的最初阶段，Orowan 环占主导地位。然而，随着塑性变形的进行，尽管许多位错环已经包围了相同的 γ' 析出物，但在 γ' 析出物中产生了越来越多的孤立的超晶格堆垛层错，表明 {111} 滑移系统对 γ' 沉淀的剪切在应变塑性变形中起着越来越重要的作用。基于实验观察，讨论了工作变形机制与HT700T加工硬化率之间的关系。